The main and probably most major issues outstanding are the
kernel/boot process - so
kernel/initscripts/olpcrd/initscripts/upstart/rainbow collection
of stuff.... of which I have no real idea about. Updates?

Peter,
Your remark does not contain any specific questions so it's a little
hard for me to give you a coherent update. Instead, I'll make some
general remarks in the hope that they will elicit further questions.
1. As has been recently pointed out, Rainbow is not currently in use
on any Sugar platform later than sugar-*-0.84 (i.e. OLPC's 8.2.*).
However, some have wondered whether it might make a reappearance in
sugar-*-0.86. To speed this outcome, I have prepared new versions of
rainbow (0.8.*) which are easy to install and test on many different
platforms. See
http://wiki.laptop.org/go/Rainbow

for current status information.

(I await further rainbow-0.8.* questions, comments, concerns, and
test results with particular interest.)
2. There is little change in the state of olpcrd and olpc-update.
Daniel Drake did some nice work in February to make the toolchain
support OFW-hosted key overlays and, so far as I know, is happily
serving Paraguay-signed leases and software updates over Paraguay's

test schools' wifi network.
(Dan -- could you please update

http://wiki.laptop.org/go/Security
with links to a description of how you've deployed these
technologies?)
(Peter -- Did you have some specific question about the technology or
about its inclusion [or lack thereof] in Fedora?)
Regards from Athens,
Michael